[Grammar] was writing OR wrote

[Tom]

Hello! Could you help me?
I have another question:
** A: Has your father finished his report?
B: Sorry, I don't know. He ______ it this morning.
A. was writing B. wrote C. has written
Which is/are right?
Thanks a lot!

 

[bhaisahab]

Hello! Could you help me?
I have another question:
** A: Has your father finished his report?
B: Sorry, I don't know. He ______ it this morning.
A. was writing B. wrote C. has written
Which is/are right?
Thanks a lot!

Which do you think is correct? Hint, there is only one correct answer.